NSSDCA ID: PSCM-00011
Availability: At NSSDC, Ready for Offline Distribution (or Staging if Digital)
Time span: 1969-08-20 to 1981-06-24
This collection consists of data from the Apollo lunar laser ranging experiments from Apollos 11, 14, and 15. The data were written originally on a CDC 6600 computer. Each physical record contains 64 logical records. An additional four characters were appended at the end of each physical record when the original tapes were duplicated on an IBM 7094 computer.
The logical records are 80 characters in length. There are two types of logical data: run data, designated by the character "Z" occurring at the beginning of the records, and shot data, designated by the character "P".
The run data recorded include a Julian date, clock error, ambient temperature (Celsius), ambient relative humidity (percent saturation), wind speed, laser energy (J*10), laser frequency (Hz*10**10), pulse length (s*10**10), observational resolution (s*10**10), photo multiplier dark count (kHz), number of shots fired in the run, and several other parameters.
The shot data recorded include the Julian date, the observed time delay (s), the observational uncertainty (s*10**10), the electronic calibration delay (s*10**10), the geometric delay (s*10**10), the ambient presure (mb*10), and other parameters.
The filtered data consist of photon detections submitted to a data filtering procedure assuming linearity of O-C residuals (the difference between the observed and calculated position) over a relatively short time interval and relying on Poisson statistics for the level of confidence in a collection identified by the filter.
The unfiltered data are real data heavily interspersed with noise photons from any of the various sources of stray light. An attempt to use the data in a simple Gaussian application would result in a solution closely adhering to the prediction ephemeris used to control the detector range grating. Some filtering process must be applied to the data for effective use.
The data provider cautions users that during the reporting interval many of the data items specified in the record format were not available. The data value provided in these cases is a null value.
Questions and comments about this data collection can be directed to: Coordinated Request and User Support Office
Name | Role | Original Affiliation | |
---|---|---|---|
Dr. J. Derral Mulholland | Data Provider | University of Texas, Austin | |
Dr. J. Derral Mulholland | General Contact | University of Texas, Austin |
McDonald Laser Ranging Station (University of Texas)
Current Lunar Laser Ranging Data Sets